Issue 04 · 12 August 2026

The ice bath did not blunt the adaptation

Three months of cold water immersion after lifting left redox gene expression and mitochondrial enzyme activity exactly where the control group left them. It is the first issue where oxidative stress is one of our standing subjects.

7 studies 16 July to 12 August 2026, a catch up window 17 min listen Listen on Spotify

Issue 04: The ice bath did not blunt the adaptation

17:08 · 12 August 2026

0:54Three months of ice baths left the redox and mitochondrial adaptations intact 3:01Carbohydrate during intervals spared muscle glycogen but not liver glycogen 5:12Short chain fatty acids delivered to the colon protected the gut barrier and spared no glycogen at all 7:18The same dose of short chain fatty acids did different things depending on where in the gut it landed 9:28An enzyme cut the bloating from a big inulin dose without changing a single breath gas 11:17Holding carbohydrate high during four days of low energy availability halved the drop in IGF-1 13:21People whose first thousand days fell under sugar rationing had lower adult cancer rates

In this issue

Randomised crossover plus parallel group trial Date verified

Three months of ice baths left the redox and mitochondrial adaptations intact

Trained men lifted twice a week for three months, half of them sitting in cold water after every session. Redox gene expression and mitochondrial enzyme activity rose the same amount in both groups.

Experimental Physiology, online ahead · Roberts et al. · The University of Queensland · 22 July 2026 · PMID 42487262

oxidative-stress recovery mitochondria

3 months
of post lifting cold water immersion, with no effect on redox gene expression or mitochondrial enzyme gains
Randomised crossover Date verified

Carbohydrate during intervals spared muscle glycogen but not liver glycogen

Sixty grams of maltodextrin during hard intervals cut muscle glycogen use by about 40 percent and left the liver untouched. Adding caffeine and four other actives cancelled the sparing, because the riders simply went harder.

American Journal of Physiology · Hannon et al. · Manchester Metropolitan University · 4 August 2026 · PMID 42552237

carbohydrate endurance-fueling metabolism caffeine

40%
less muscle glycogen used with carbohydrate, with no change in liver glycogen use
Randomised double blind crossover Date verified

Short chain fatty acids delivered to the colon protected the gut barrier and spared no glycogen at all

A modified starch that releases short chain fatty acids in the colon lowered markers of intestinal barrier damage during 90 minutes of cycling. Muscle glycogen and 5 km time trial performance were untouched.

The Journal of Physiology, · Karl et al. · U.S. Army Research Institute of Environmental Medicine · 11 August 2026 · PMID 42581384

gut-health fiber endurance-fueling GI-distress

5 s
difference in 5 km time trial, with a confidence interval running from 44 seconds faster to 54 seconds slower
Randomised crossover PubMed records 10 August 2026, Crossref records 11 August 2026. The earlier date is cited.

The same dose of short chain fatty acids did different things depending on where in the gut it landed

Twenty eight healthy adults received an identical short chain fatty acid dose targeted either to the small intestine or to the colon. Colonic delivery released more PYY, small intestinal delivery released more GLP-1, which is the opposite of what the authors expected.

The American Journal of · Rosseel et al. · KU Leuven · 10 August 2026 · PMID 42575284

gut-health fiber metabolism microbiome

230 mmol
the identical dose in both arms, with opposite hormone responses depending on where it was released
Randomised double blind crossover PubMed records 11 August 2026, Crossref records 12 August 2026. The earlier date is cited.

An enzyme cut the bloating from a big inulin dose without changing a single breath gas

Thirty healthy adults ate 25 grams of inulin with either a fructan digesting enzyme or a placebo capsule. Symptoms were milder over the following day, while breath hydrogen and methane were identical.

The Journal of Nutrition, · Mah et al. · Biofortis Inc. · 11 August 2026 · PMID 42580594

fodmap gut-health GI-distress fiber supplements

25 g
of inulin in one sitting, with milder symptoms and unchanged breath gases when an enzyme was taken alongside
Randomised crossover Posted online 16 July 2026. Assigned to the 1 August 2026 print issue. Cite the July date.

Holding carbohydrate high during four days of low energy availability halved the drop in IGF-1

Sixteen adults spent two separate four day blocks at the same low energy availability, once on 1.5 and once on 4.0 grams of carbohydrate per kilogram per day. The endocrine response tracked the carbohydrate, the shift in fuel use did not.

Journal of Applied Physiology · Nusser et al. · Technical University of Munich · 16 July 2026 · PMID 42461760

carbohydrate energy-availability metabolism female-athletes

2x
larger fall in IGF-1 when carbohydrate was low, at the same energy availability
Natural experiment in a prospective cohort Published online 4 August 2026, print issue 11 August 2026. An earlier medRxiv preprint of the same analysis appeared 22 November 2025. Cite the August 2026 peer reviewed version.

People whose first thousand days fell under sugar rationing had lower adult cancer rates

British sugar rationing ended abruptly in September 1953, which splits a UK Biobank birth cohort almost cleanly in two. Those conceived and born under rationing showed lower rates of several cancers decades later, and were still eating less sugar in their fifties.

Proceedings of the National · Zhu et al. · China Agricultural University · 4 August 2026 · PMID 42550905

general-nutrition carbohydrate diet-quality

1000 days
the exposure window, defined by a rationing policy that ended in September 1953